The observer pattern is a software design pattern in which an object, called the subject, maintains a list of its dependents, called observers, and notifies them automatically of any state changes, usually by calling one of their methods.
In computer programming, the strategy pattern (also known as the policy pattern) is a behavioural software design pattern that enables selecting an algorithm at runtime.
This document aims to give an easy way to install both Python 2 &3. Python is a useful script programing language, but I never use it before. This is the first time I used. Recently, my manager wants me to write a tool to convert in game xml string table to Excel file. We must use Python3 (Unicode support) to deal with multi-language, and sadly our game compiler is based on Python 2… So, it’s also my first problem to face with.